缓冲流和统计字符出现个数的练习

package test1; import org.junit.Test; import java.io.*; import java.util.HashMap; import java.util.Map; import java.util.Set;

public class buffer {

@Test public void bufferReder() { FileReader fileReader = null; FileWriter fileWriter = null; BufferedReader bufferedReader = null; BufferedWriter bufferedWriter = null; try { fileReader = new FileReader(new File("D://test3.txt")); fileWriter = new FileWriter(new File("D://test33.txt")); bufferedReader = new BufferedReader(fileReader); bufferedWriter = new BufferedWriter(fileWriter); char[] cbuf = new char[5]; int len; while ((len = bufferedReader.read(cbuf)) != -1) { bufferedWriter.write(cbuf, 0, len); } } catch (IOException e) { e.printStackTrace(); } finally { try { bufferedReader.close(); } catch (IOException e) { e.printStackTrace(); } try { bufferedWriter.close(); } catch (IOException e) { e.printStackTrace(); } try { fileReader.close(); } catch (IOException e) { e.printStackTrace(); } try { fileWriter.close(); } catch (IOException e) { e.printStackTrace(); } } } //综合练习：读取一个文档中的所有字符出现的次数 @Test public void Test() { FileReader fileReader = null; FileWriter fileWriter = null; BufferedReader bufferedReader = null; BufferedWriter bufferedWriter = null; try { fileReader = new FileReader(new File("D://十不准.docx")); fileWriter = new FileWriter(new File("D://统计十不准.docx")); bufferedReader = new BufferedReader(fileReader); bufferedWriter = new BufferedWriter(fileWriter); Map<Character,Integer> map = new HashMap<>(); int c = 0; while ((c = bufferedReader.read())!=-1){ char ch = (char)c; if(map.get(ch)==null){ map.put(ch,1); }else{ map.put(ch,map.get(ch)+1); } } Set<Map.Entry<Character,Integer>> entries = map.entrySet(); for (Map.Entry<Character,Integer> enty: entries) { switch (enty.getKey()){ case ' ': bufferedWriter.write("空格="+enty.getValue()); break; case '\t': bufferedWriter.write("Tap键盘="+enty.getValue()); break; case '\n': bufferedWriter.write("换行符="+enty.getValue()); break; case '\r': bufferedWriter.write("回车="+enty.getValue()); break; default: bufferedWriter.write(enty.getKey()+"="+enty.getValue()); break; } bufferedWriter.newLine(); } } catch (IOException e) { e.printStackTrace(); } finally { try { bufferedReader.close(); } catch (IOException e) { e.printStackTrace(); } try { bufferedWriter.close(); } catch (IOException e) { e.printStackTrace(); } try { fileReader.close(); } catch (IOException e) { e.printStackTrace(); } try { fileWriter.close(); } catch (IOException e) { e.printStackTrace(); } } }

}